1. Field of the Invention
The present invention relates to an input pen that is held in an input device, such as a personal digital assistant.
2. Description of the Related Art
Although some users use a standard input pen that is delivered as an attachment together with an input device, such as a personal digital assistant, when the input device is bought, for writing information, many users who bought an input device use an additionally bought input pen superior in function to the standard input pen. However, respective input pen holding parts of different personal digital assistants are different from each other in terms of inside diameter and holding structure, and hence the users are required to buy a special input pen for the personal digital assistant bought by the users.
A standard input pen designed for a particular personal digital assistant cannot be used when the particular personal digital assistant is replaced with a different personal digital assistant. An input pen bought by a user for use in combination with the user""s personal digital assistant becomes useless when the user buys a new personal digital assistant, and hence the user needs to buy another input pen for the new personal digital assistant.
According to a first aspect of the present invention, an input pen to be used in combination with an input device comprises: a barrel; openings formed in the barrel; stopping members respectively having projections fitted in the openings of the barrel, respectively; and an elastic member extended between the stopping members so as to make the projections project properly outside through the openings, respectively; wherein the input pen is held in an input pen holding part of the input device with the stopping members engaged with the input pen holding part.
In the input pen according to the first aspect of the present invention, the barrel is provided in diametrically opposite parts of an inner surface of its back part with longitudinal grooves extending forwardly from a back end thereof, the openings are formed in proper parts of the grooves, the projections of the stopping members placed in the two grooves project through the openings of the barrel, respectively, and the elastic member is a compression coil spring having opposite ends inserted in holes formed in the stopping members placed opposite to each other to push the stopping members outwardly. In the input pen according to the first aspect of the present invention, the elastic member can have a C-shaped section, and the elastic member can be formed integrally with the stopping members. In the input pen according to the first aspect of the present invention, a front input member formed of a synthetic resin is placed in a front part of the barrel, a back input member formed of a soft material is placed in a back part of the barrel, and the back input member is formed integrally with the stopping members.
According to a second aspect of the present invention, an input pen to be used in combination with an input device comprises: a barrel; elastic parts formed in the barrel and capable of being elastically bent; and projections formed on the elastic parts; wherein the input pen is held in an input pen holding part of the input device with the projections pressed against an inner surface of the input pen holding part of the input device.
The elastic parts can be formed in the barrel by cutting U-shaped slits in the barrel. Alternatively, the elastic parts can be formed in the barrel by cutting longitudinal, parallel slits in the barrel.
In the input pen according to the second aspect, an elastic member may be placed in the barrel at a position corresponding to the elastic parts of the barrel.
According to a third aspect of the present invention, an input pen to be used in combination with an input device comprises: a barrel; openings formed diametrically opposite to each other in the barrel; a tubular member fitted in the openings; an elastic member held in the tubular member; and stopping members inserted in opposite end parts of the tubular member, respectively, and pressed by the elastic member so as to project properly from opposite ends of the tubular member; wherein the input pen is held in an input pen holding part of the input device with the stopping members engaged with an inner surface of the input pen holding part of the input device. In the input pen according to the third aspect of the present invention, the opposite ends of the tubular member may be bent radially inwardly to hold the stopping members in the tubular member. In the input pen according to the third aspect of the present invention, the elastic member may be a coil spring.